In UK patent application No. 2213121 there is proposed an apparatus for orientating containers connected together by a plastic coupler which is relied upon to prevent inadvertent rotation of the individual containers from their desired orientated positions, but the speed of operation of the apparatus in terms of the numbers of packs which can be handled in a given time is limited by the strength of the coupler and due to the machine construction.
In the machine of UK patent specification 2213121, a container multipack is advanced to an orientation station by helical scrolls which have their axes parallel and extending in the feed direction. When the scrolls are rotated they first engage the leading containers of the multipack and then, as the multipack moves forwardly, the scrolls engage in turn the successive ranks of containers in the multipack. It has been found that if the scrolls are rotated at high speed to produce rapid advancement of the multipack, the coupler can be stretched and deformed, because the scrolls initially engage only the cans in the first rank, with the result that the machine malfunctions. In order to be acceptable for incorporation in modern beverage can packaging lines, which typically have operating speeds of 3000 cans per minute, or even higher, it is desirable that a can orientation machine should be capable of handling at least 100 multipacks per minute, depending upon the number of containers included within the multipacks. None of the can orientation machines previously proposed are capable of operating satisfactorily at such speeds, which is one reason why they have not gained commercial acceptance.
In UK Patent No. 1247450 there is disclosed an apparatus for orientating containers grouped in a multipack wherein clamps are provided for transferring the multipacks to the orientation station. The clamps are controlled by cams so that they are pivoted inwardly and outwardly for engaging and releasing the containers in a multipack and are reciprocated backwards and forwards for advancing successive multipacks. The maximum speed which can be achieved by means of such a transfer mechanism is also severely restricted.
In the prior art apparatus of both GB-A-2213121 and GB 1247450, upon arrival of a multipack at the orientation station the containers are raised by respective lifting members to engage the upper ends of the containers with respective chucks which are driven to rotate the containers during the orientation process, the lifting members being freely rotatable about their respective axes. The lifting members are mounted on a common carrier which is itself raised and lowered by a cam arrangement. A cam actuated lifting assembly has been found unacceptable for high speed operation because it causes container bounce and hence a level of vibration which can not be tolerated. With the lifters supported by a common carrier, the mass raised and lowered each time is substantial, which adds to the vibration problem.
In order to achieve accurate orientation of the containers it is necessary that they should engage precisely the chucks by means of which the containers are rotated. If the containers are subjected to very rapid lifting by means of lifting members which are engaged with the container bottoms, the containers are liable to tilt so that they do not engage correctly the chucks. Furthermore, when the lifting members are lowered the cans must disengage themselves from the chucks. If the containers do not have a good fit with the chucks there is a chance that they will not be reliably rotated due to slipping between the containers and chucks, but if there is a close fit the containers may fail to disengage from the chucks so that operation of the can orientation machine, and possibly the entire container packaging line, must be interrupted. These problems are not addressed by the aforementioned British patent specifications and the apparatuses disclosed therein do not offer any solution to them.
It is a primary object of the present invention to provide a container orientation apparatus which can operate reliably at high speed to enable the apparatus to be incorporated in a container filling and packing line.
Another object of the invention is to provide a container orientation apparatus having a feed system capable of delivering successive multipacks to an orientation station at a high feed rate without risk of damage to the coupler holding together the containers of the multipack or to the containers.
A further object of the invention is to provide a container orientation apparatus having independent lifting members for raising the respective containers of a multipack at an orientation station.
A still further object of the invention is to provide a container orientation apparatus having means to guide the containers into engagement with the chucks, and having means to ensure disengagement of the containers from the chucks.
It is also an object of the invention to provide a container orientation apparatus which is easily adjustable to suit containers of different heights.